The invention relates to a machine having a rotor which is mounted such that it can rotate about a rotation axis and                comprises an uncooled rotor body which, on an outside, has recesses or flats, in the cross-sectional surface area of which at least one rotor winding is arranged, which is accommodated in a cryostat with a cryostat wall and can be cooled to low temperature, and        is provided with a holding and/or supporting device for transmission of forces acting on the rotor winding via the cryostat wall to the rotor body,wherein        the holding and/or supporting device contains at least one supporting element via which heat is transmitted from the rotor body to the rotor winding.        
A corresponding machine is known from DE 10 2004 039 855 A1.
In the case of rotating machines with a rotor winding which is cooled to low temperature below 80 K, in particular a superconducting rotor winding, the torque is partially incurred on the cold windings of the rotor. In order to allow it to be utilized, the applied torque must be transmitted to a hot shaft. An apparatus that is suitable for this purpose must on the one hand be able to transmit the torque, which in large machines may be several 100 kNm, while on the other hand the holding apparatus for the superconducting rotor windings must provide good thermal insulation. Only if the thermal insulation is good enough is it possible to keep the rotor windings at the low temperature required for superconduction, with a limited amount of cooling.
In the case of machines known from the prior art, the superconducting rotor windings are held by a winding mount which is in turn located on a central mount core. One such arrangement is known from DE 199 43 783 A1. The rotor windings, winding mount and mount core in a machine such as this are at a low temperature, as required for superconduction. The large mass of the cold mount structure in machines of this type result in very long cooling-down times, and the need to use powerful cooling systems. A further machine of this type is disclosed in WO 98/02053.
Because of the technical problems mentioned above, it is advantageous for large machines for at least a part of the mount structure of the rotor windings not to be cooled down to the low temperatures required for superconduction, that is to say to use an at least partially warm mount structure. A machine of this type is disclosed, for example, in DE 10 2004 039 855. In the case of machines of this type, the superconducting rotor winding is located in a cryostat, which is located on the outside of the uncooled rotor body, in a corresponding recess or on a corresponding flat. In the case of machines such as these, with a so-called warm mount structure, it is necessary to attach the superconducting rotor windings, which have been cooled to low temperatures, to the warm rotor body by means of a suitable holding and/or supporting apparatus. One such holding and/or supporting apparatus is known from DE 103 03 307 A1.
In the case of the machines known from the prior art, losses take place by thermal conduction from the superconducting rotor windings, which are at low temperatures, via the various parts of a holding and/or supporting apparatus. Appropriate cooling power must be supplied via the cooling system into these areas of the machine in order to maintain the low temperatures, as required for superconduction, in the area of the rotor windings.